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sikend667

EJ22T swap issues

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ok so im stuck..... got the motor dropped, wiring ran, and now i have no spark.... ignighter tested good coil tested good replaced the crank and cam sensors and still nothing..... any ideas? ecu has power and i have fuel only things not hooked up are the o2 sensor, knock sensor, and i hardwired the fuel pump..... any suggestions would be appriciated. the harness has been completely stripped so no test connecters under dash stuff etc.

 

so basically im looking for what circuts NEED to be there in order for the computer to send a signal to the coil

 

thanks

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compression check?

 

The only reason I ask is that when I did my ej swap I replaced the timing belt and had the cam gears off a couple teeth re timed the cams and it fired right up.

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there is no spark at all pulled the plug wires and nothing there tested for voltage to the coil its good and to the ignighter its good..... but no spark at all.... ill try it (hell ill try anything at this point) but i doubt very much that timing is the issue

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the crank and cam sensors were very bad when i got the engine they have since been replaced. i have everything else but ZERO spark... spent all weekend milling over wiring diagrams and cant seem to find any reason why it wont spark..... i know its bound to be somthing dumb that im not seeing.....

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It's probably in the yellow wire that is tied to the IG. on circuit that powers the Coil, Transistor, IAC, and a whole bunch of other stuff.  That wire is notoriuosly cut out of the harness.  It has a crimp splice that is by the fuse box, and is often cut out as it doesn't seem to be coming from either the Intake or ECU, but it is.

 

Also maybe the Start signal wire?

 

Oh and what ALT are you running?  There has been a bad batch going round that when tied to the ALT IG. circuit (yellow wire mentioned above) will trip out the ECU like try to reset it over and over?  If you have you're ALT hooked up like that, like it would have been in the Legacy, and it's a new alt, unhook it then try to start.

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start signal wire is which pin? i do have a random yellow/red wire that i cant figure out what it does the alt is early impreza ive tryed it with and without the alt so i dont think its that.... what gauge is this IG. on wire you speak of?

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start signal wire is which pin? i do have a random yellow/red wire that i cant figure out what it does the alt is early impreza ive tryed it with and without the alt so i dont think its that.... what gauge is this IG. on wire you speak of?

 

That would be it.  Thick red yellow wire.  Tied in with the Clutch/start relay ciruit in the IMP.  If it's a big fat wire, but gets small right before the ECU that's definately it. 

 

Hook it to the "5"th pin in your IG. switch. The one by itself at the corner.   Your existing harness may or may not have a pin on the body side, but it should be there in the connector coming from the switch.

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Starter signal will not effect spark. It just changes the fuel trims (choke).

 

 

First thing I would do is un-hardwire the fuel pump (or, at the very least, hook a test light to that wire on the ECU) to make sure that your ECU is powering up correctly. If your ECU isn't priming the fuel pump, you have bigger and simpler problems.

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Starter signal will not effect spark. It just changes the fuel trims (choke).

 

Well, depending on what circuit he hooked into for IG. switched power the IG. switched power could be momentatrily dropping off while cranking.

 

It's my understanding that the start signal wire is there to solve that, providing strable voltage during cranking, in addition to it's fuel trim function. I feel like there should still be spark either way, but I think it's worth a try, I've seen/heard of lots of swaps not starting til that wire is hooked up.

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Well, depending on what circuit he hooked into for IG. switched power the IG. switched power could be momentatrily dropping off while cranking.

 

It's my understanding that the start signal wire is there to solve that, providing strable voltage during cranking, in addition to it's fuel trim function. I feel like there should still be spark either way, but I think it's worth a try, I've seen/heard of lots of swaps not starting til that wire is hooked up.

 

I daily drove my car for a year with that wire dangling. It cranked longer, especially in the winter (no choke), but it still started every time.

 

 

I don't believe that circuit is designed to hold any sort of load (hence the small gauge wire going into the ECU), so if your voltage drops elsewhere, I think you need to resolve that. But, I haven't tested it, or seen any concrete information either way.

 

Of course, it should be hooked up for correct operation, but I don't believe, for a second, that that has anything to do with the issue seen here.

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ok plan on rewiring the fuel pump this weekend. any other circuits that are MANDITORY that may have been overlooked?

 

In my experience, the ECU will prime the fuel pump at least once if the power and grounds are all connected correctly. If the starter signal has been triggered a few times (there's probably a total time equation of somesort in the ECU program) with no signal from the crank angle sensor, it will stop priming the fuel pump. 

 

Truth be told, the fuel pump circuit isn't MANDATORY, as the engine will run with the pump on it's own dedicated source. But, it's a pretty simple circuit, and will give you quite a bit of insight on what the ECU is doing.

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ive got no priming from the ecu to the fuel pump.... now what lol

 

This is what I suspected. You're not looking at ignition components, as you have a bigger/simpler problem. Your ECU is not powering up correctly.

 

Pull up an ECU pinout for your ECU, and triple check that you have good power and ground to all the wires that need it.

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i dogknoted the grounds together and grounded them to the chassis should i undo that and run individual ground wires? also does the ECU case need to be grounded? it currently lives in a water tight case inder the hood

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Everything should ground through the intake wiring harness.  If you cut the grounds off near the ECU then grounded them seperate, there may be other items out at the intake that aren't grounded.

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Everything should ground through the intake wiring harness.  If you cut the grounds off near the ECU then grounded them seperate, there may be other items out at the intake that aren't grounded.

 

Yep. All engine related parts should be grounded to the engine block. Adding a contact to the chassis isn't going to hurt anything, but if the wires to the block were removed, that could.

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ok well that might be the issue then as EVERYTHING is grounded to the chasis.... what abouth the ECU itself. it is in a plastic watertight box should it be grounded as well?

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The ECU case doesn't need to be grounded. It gets everything it needs through the harness.

 

 

 

Yea, when I've done EJ swap harnesses, they require no ground hookup. Just plug into the engine harness, and everything needed is right there on the block. Simple, and extremely functional.

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thank you chux as usual you are one of the best resources out there..... i will attempt regrounding everything this weekend and see if that solves the improper powering issue

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Does the CEL illuminate with the key on?

 

Did you give power to the light green wire to trigger the IG. relay?  Can you hear the relay working?

 

ECU must not be powered properly.

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relay works check engine light comes on

 

im about a week from saying screw it and ordering an aftermarket ECU

Edited by sikend667

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